Minecraft Discontinued Features Wiki:Active Bounties

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Java Edition

Negative XP Orbs

Negative xp orbs were first theorized in November of 2020 by Bluecrab2 and Bayugoon. During this same conversation, negative xp orbs were proven obtainable through commands, and were thus confirmed to exist. There are multiple potential methods to achieve negative xp orbs. Usefulness for these orbs would be to create negative durability equipment of any variety, as negative xp orbs that are absorbed while holding mending items decreases the durability instead of increasing.

• It was initially theorized that negative xp values on the player could be reached by jumping in Beta 1.9 Pre-release 2, however this was disproved as it hit a hard block at half the 32 bit integer limit

• The XP command is usable in survival in 17w45a. Using this command you can assign a negative value, however it only effects the player's Score level, it does not modify the XpLevel.

• XP orbs merge to combine xp values, however there is a limit disallowing them from ever reaching a negative value. Code has been tested in 1.12, and the game analyzed in 1.17, with repeat behavior in both cases.

• Xp can be mass duplicated in Beta 1.8 Pre-release 2, allowing for the player to reach a negative value. This can be done by dying with xp while on a server, which doubles the dropped experience each time. A player could potentially die with a negative xp value in a future version and then drop negative xp orbs. All tested versions are in the table below.

Version	Result
1.12.2	Dropped 0 XP

• Smelting 2,147,483,647+ items from a specific furnace recipe sets the respective RecipeUsed value within the furnace negative in certain versions, however this was later proved to overflow to 0 in certain specific versions. Technically speaking, considering this value is multiplied by the xp for a given recipe, when mining the furnace, the xp dropped from it should be negative. However, through extensive testing, mining a furnace with negative recipes used always drops 0 xp (tested in versions listed below). Many differing methods of breaking have been tested, all with the same outcome. Potentially taking an item from the furnace output slot would have a different outcome. Furnaces only store experience from 18w09a onwards, meaning these should be the versions to search through. Code analysis of furnace xp storage has yet to be completed to properly debunk this method. Note even if this method is proven to work, which current research has proved unlikely, it would still be infeasible since it requires over 2 billion items to be smelted.

Version	Result
1.19.4	Dropped 0 XP

• Code analysis of many versions from the introduction of XP (in the Beta 1.8 prereleases) to the present day show that any source of XP orbs being created will have a value between 1 and 2477, as a result of the code that splits XP drops into separately sized orbs. If any method of negative XP orbs is to be found, something must be found (likely in a snapshot or other development version) that does not use the splitting code. If such a method exists, then it can be used to create a negative XP orb by obtaining a value higher than 2477, such that value % (modulo) 65536 > 32767 (32768-65565 is the first valid range). The value variable is cast from an integer to a short when writing to NBT, allowing the value to overflow such that it becomes negative if the value is in a valid range.

Level.dat Deletion Methods

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The goal of this bounty is to develop a method to delete level.dat in every version, essentially from Beta through modern versions, with a focus moreso on modern versions. The point of this bug is to allow world save insertion without file moving, so worlds can be loaded in versions while bypassing downgrade and experimental world restrictions.

One Item Villager Trades

There is a report in October of 2021 of a 12w21a server crashing and then converting all villager trades to 1 item for 1 item. This would allow for several varieties of discontinued trade amounts were it to be proven.

• The server was not confirmed to be entirely vanilla, and the reporter did not have access to a world download or crash logs for verification. As a result of this, server side hosting mods such as bukkit should be considered when testing to potentially debunk this bounty.

• Crashing a singleplayer world in 12w21a has had varying results, however so far it has not replicated the described behavior. Crashing a world while loading a villager has resulted in the villager's region not loading in correctly and has also had a separate occurrence of nothing happening during the crash. The villagers would also reset trades, however they would reset within the normal trade ranges. Crashing the world while having the villager's GUI open also sometimes caused the villager to disappear.

• Since the bug occurred on a 12w21a server, there is the possibility it is a server specific bug. Shutting down a server while having a villager gui open was not able to reproduce the bug, however crashing the server while in game has yet to be tested. There is also the potential of this bug being based on precise timing, or also the possibility of the crash needing to occur as the villager is refreshing trades or unlocking new trades.

Extra Durability Iron Pickaxe

This bug was first showcased in September of 2012 in a youtube video by Mogswamp, and brought to our attention in January of 2022.In this video, Mogswamp explains he has an invincible pickaxe, and he is not sure how it happened. According to him, he was using it in the nether to hit mobs, and the pickaxe durability was not appearing. That is when he realized it seemed to have infinite uses. Further research shows the pickaxe first appearing in episode 18 at roughly 15 minutes in, when it is being used to mine some blocks around a blaze farm. In episode 19 of the series, he is shown using the pickaxe to mine approximately two stacks of cobblestone (128 uses). At a later point in the video, a timelapse is run where he uses the same pickaxe to mine another roughly one to two stacks, and his inventory count implies he used the same iron pickaxe to mine at least almost 14 stacks (896 additional uses). He then uses it later again to mine some netherrack towers, adding another roughly 32 blocks, and he still has the pickaxe at the end of the episode. The pickaxe continued to appear in episode 20, where it was used to mine additional various blocks. In episode 21 the pickaxe does appear to be missing; it is unclear if the iron pickaxe being used within the episode is the extra durability one now taking durability or a newly crafted one. Within the episode he states that he likely just crafted a new one, and the infinite pickaxe still exists, however in the very next episode he confirmas he either lost the pickaxe or it started taking durability. This statemenht was conflicted at a later date when Mogswamp stated the pickaxe broke after leaving it mining overnight, producing approximately 3 double chests of cobble (10368 blocks).

Bayugoon also reported the same bug happening to him on an undetermined Beta server with a diamond pickaxe. The version this would have occurred on is unknown, and he reports that the pickaxe simply went back to normal after some time. Mogswamp's pickaxe and Bayu's pickaxe could have been entirely different and unrelated events. The reasoning behind this is the large version gap. Additionally, Mogswamp has a lot of evidence essentially disproving the bug to be visual, whereas Bayu's likely could have been an odd clientside Beta error where the durability bar stopped rendering.

• There is the possibility of the entire bug being purely visual. However, this is incredibly unlikely if not debunked entirely. All statements provided by Mogswamp make it sound as if the pickaxe mined thousands of blocks before eventually breaking. Considering an iron pickaxe only has 250 durability normally, any mining surpassing this has to be an actual result of durability changes, and can not be purely visual. Video playback shows the pickaxe mining at least 200 blocks, and it is likely playing it back further and more in depth analysis will show more than 250 blocks mined by a single pickaxe. The statements made also correspond with the behavior of a pickaxe with a negative damage value. Assuming this is the case, it would be capable of mining roughly 32.7k blocks before underflowing and changing to 0 durability, and thus breaking. Considering a single nighttime mining session resulted in roughly 10k blocks, only 3 of these afk sessions would break an extra durability pickaxe.

• Optifine was used in the series, and as a result of that forge was also used as a mod loader. While unlikely a basic clientside mod such as optifine would impact an item's durability, it cannot be fully ruled out, and testing should consider the possible use of mods.

• Mogswamp himself stated the most likely way the pickaxe was obtained was through regular crafting. A version range could be narrowed down from the episode backlog, and then crafting could be tested in all of these versions. Mogswamp has stated that he did have a tendency to go to snapshots back during this time, so all versions between 1.1 and 1.3.2 should be considered. However, due to the prominence of this bug and the amount of casual playthroughs on most of these versions, it is likely a bug of this caliber would have been accidentally found by another person. It is more likely that if the pickaxe was crafted normally that there was some action performed using the pickaxe causing the damage value to go negative.

• Considering the world was superflat, all diamond tools were traded for. As a result of this, there is the chance the iron pickaxe was also traded for. However, similar to the crafting theory, it is likely this bug would have been found accidentally just from trading in 1.3. There are two possible types of trade to achieve an iron pickaxe: A blacksmith will sell an iron pickaxe, and a cleric will enchant an iron pickaxe. The blacksmith trade is far more likely, as the cleric will apply enchantments onto the pickaxe, which are absent from the example pickaxe. Additionally, this theory is more likely, as an iron pickaxe could have been purchased to unlock later trades.

• Repairing tools is used to combine negative durability tools to go lower. As a result, it is a logical leap to assume repairing tools could also cause this bug. The way repairing tools works is it combines the durability of tool 1 with tool 1, and then adds an additional 5% of the tool's durability. Potentially in an obscure version, combining two almost full durability tools could cause the damage value to go past 0 (essentially combining two durability values + 5% to reach a value greater than the base durability). Anvils did not yet exist in the version where this pickaxe existed, so it was not a result of repairing in an anvil.

• Iron pickaxes do generate in blacksmith loot, so there is a chance that in a certain version a pickaxe generated in this loot table has a negative damage value. Similar to the above theories, it is likely this would have been found already from casual playthroughs.

• Mogswamp claimed he first noticed this bug while hitting mobs. As a result, possibly the pickaxe took damage incorrectly while being used to attack mobs, and received a negative damage value.

• Considering it was a pickaxe, it could have been a damage value resulting from mining. A possible theory could be instant mining of a block resulted in damage values to the pickaxe being applied incorrectly.